(a) Technical Field
The present invention relates to a system and method of controlling an inverter in an eco-friendly vehicle. More particularly, it relates to a system and method which reduces noise caused by the switching frequency of an inverter by changing the frequency range of generated noise according to the inverter switching frequency of an eco-friendly vehicle.
(b) Background Art
Generally, eco-friendly vehicles including Pure Electric Vehicles (EV), Hybrid Electric Vehicles (HEV), and Fuel Cell Electric Vehicles (FCEV) use an electric motor as at least one driving source for driving. In particular, eco-friendly vehicles typically utilize a drive a motor to convert a direct current stored in a main battery into a three-phase alternating current to drive a motor, and deliver a driving force of the motor to one or more driving wheels of the vehicle.
In eco-friendly vehicles, kinetic energy is converted into electric energy through regenerative braking upon deceleration, and electric energy is typically stored in a battery. Thereafter, energy stored in the battery is reused for driving of a motor to improve the fuel efficiency.
In a motor system which includes both an inverter and a motor of an eco-friendly vehicle, a high frequency noise is often generated during driving/regenerative driving when the inverter is operating. FIG. 1 is a view illustrating noise generated during the regenerative braking (i.e., corresponding to a section in which the speed of a motor is decelerating) when the switching frequency of an inverter is 4 kHz in a motor system.
As shown in FIG. 1, when the switching frequency of the inverter is 4 kHz, noise generated during driving is within a range of 2 kHz to 5 kHz that is most sensitive to human ears. When such noise occurs, a driver or a passenger may feel discomfort.
In the analysis graph of FIG. 1, the horizontal axis (X-axis) denotes time, and the vertical axis (Y-axis) denotes frequency. As shown in FIG. 1, noise occurrence portions are concentrated within about 2 kHz to 5 kHz (i.e., the region between dotted lines).
Accordingly, there is a need for a system and method of moving the frequency range of noise out a range between 2 kHz to 5 kHz (refer to equal-loudness contour curve) that is known as the most sensitive frequency to the ear.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.